A polycarbonate resin is a thermoplastic resin formed by condensation-polymerization of an aromatic diol such as bisphenol A with a carbonate precursor such as a phosgene, and has excellent impact strength, dimensional stability, heat resistance, and transparency, etc. Thus, the polycarbonate resin has application in a wide range of uses, such as exterior materials of electrical and electronic products, automobile components, building materials, and optical components, etc.
In recent years, application of the polycarbonate-based material to portable electronic devices such as smart phones, mobile phones, or the like, has been reviewed. However, when the polycarbonate-based material is used, impact strength in a low-temperature use environment, etc., is not sufficient, and when coating is performed to satisfy recent high demand related to design, the polycarbonate-based material has a difficulty in being applied due to weak chemical resistance, etc.
In addition, there is a growing need for a molded article formed using the polycarbonate-based material to be thinner according to recent demand for designs of smart phones, etc. For this purpose, the polycarbonate-based material is required to exhibit high fluidity in a molten state, thereby exhibiting excellent thin film formability. However, it is true that conventional polycarbonate-based materials do not exhibit sufficient fluidity and thin film formability.
In order to solve the above-described problems, an attempt to add an impact-reinforcing agent, etc., to the polycarbonate-based material to reinforce impact strength has been made. However, when the impact-reinforcing agent at a predetermined level or more is added to a thinned molded article so as to achieve an appropriate level of impact strength, gas, etc., derived from the impact-reinforcing agent during molding occur, causing problems such as appearance defects of the molded article, and discoloration, etc., at high temperature molding.
Further, it is true that even if several additives are used, it is difficult to simultaneously achieve impact strength and high fluidity (thin film formability). When it is attempted to achieve these properties only by adding the additives, there is limitation in that there are many cases that considerable contents of additives are required to be added, and thus, physical properties of the polycarbonate-based material itself are reduced.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.